<android.support.design.widget.AppBarLayout
  android:layout_width="match_parent"
  android:layout_height="256dp"
  android:fitsSystemWindows="true">
  <android.support.design.widget.CollapsingToolbarLayout
   android:id="@+id/collapsing_toolbar_layout"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   app:contentScrim="#30469b"
   app:expandedTitleMarginStart="48dp"
   app:layout_scrollFlags="scroll|exitUntilCollapsed">
   <ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scaleType="centerCrop"
    android:src="@mipmap/bg"
    app:layout_collapseMode="parallax"
    app:layout_collapseParallaxMultiplier="0.7" />
   <android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    app:layout_collapseMode="pin" />
  </android.support.design.widget.CollapsingToolbarLayout>
 </android.support.design.widget.AppBarLayout>

<android.support.design.widget.CoordinatorLayout 
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context=".MainActivity">
 <android.support.design.widget.AppBarLayout
  android:layout_width="match_parent"
  android:layout_height="256dp"
  android:fitsSystemWindows="true">
  <android.support.design.widget.CollapsingToolbarLayout
   android:id="@+id/collapsing_toolbar_layout"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   app:contentScrim="#30469b"
   app:expandedTitleMarginStart="48dp"
   app:layout_scrollFlags="scroll|exitUntilCollapsed">
   <ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scaleType="centerCrop"
    android:src="@mipmap/bg"
    app:layout_collapseMode="parallax"
    app:layout_collapseParallaxMultiplier="0.7" />
   <android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    app:layout_collapseMode="pin" />
  </android.support.design.widget.CollapsingToolbarLayout>
 </android.support.design.widget.AppBarLayout>
 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  app:layout_behavior="@string/appbar_scrolling_view_behavior">
  <android.support.v7.widget.RecyclerView
   android:id="@+id/recyclerView"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:scrollbars="none" />
 </LinearLayout>
</android.support.design.widget.CoordinatorLayout>

 Toolbar mToolbar = (Toolbar) findViewById(R.id.toolbar);
  setSupportActionBar(mToolbar);
  getSupportActionBar().setDisplayHomeAsUpEnabled(true);
  mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    onBackPressed();
   }
  });
  //使用CollapsingToolbarLayout必须把title设置到CollapsingToolbarLayout上，设置到Toolbar上则不会显示
  CollapsingToolbarLayout mCollapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar_layout);
  mCollapsingToolbarLayout.setTitle("CollapsingToolbarLayout");
  //通过CollapsingToolbarLayout修改字体颜色
  mCollapsingToolbarLayout.setExpandedTitleColor(Color.WHITE);//设置还没收缩时状态下字体颜色
  mCollapsingToolbarLayout.setCollapsedTitleTextColor(Color.GREEN);//设置收缩后Toolbar上字体的颜色